The invention relates to the catalytic codimerization of norbornadiene and 1,3-pentadiene. Particularly the invention relates to the preparation of an olefinic codimer of norbornadiene and 1,3-pentadiene using a specified catalyst system. Hydrogenation of the olefinic codimer yields a saturated codimer having utility as a high energy fuel or a diluent for such fuels. The pentadiene is referred to hereinafter as PD.
High energy fuel, which is often referred to as a high density fuel, can be used in either jet or rocket propulsion. Jet propulsion includes a jet engine which can be used for a missile plane and others and includes the three basic types, i.e., ramjet, turbo-jet and pulse jet. The term rocket generally refers to a device containing its own oxygen or oxidizing agent.
Norbornadiene (I) is also known as bicyclo-(2.2.1) heptadiene-2,5. A method of preparation is disclosed in U.S. Pat. No. 2,875,256 issued Feb. 24, 1959. Hereinafter, norbornadiene is referred to as NBD. The latter can be represented by either one of the following structural formulas: ##STR1##
NBD can be easily dimerized to an exo-exo hexacyclic dimer. Thus one problem in reacting NBD with another hydrocarbon reactant is to minimize the formation of the foregoing dimer while encouraging the formation of the desired codimer.
A. Greco et al, in the Journal of Organic Chemistry, Vol. 35, No. 1, Jan. 1970, page 271 in article titled "Catalytic Norbornadiene-Butadiene and Norbornadiene-1,1-Dimethylallene Codimerization" discloses using bis(cyclooctatetraene) iron or FeCl.sub.3 -(iC.sub.3 H.sub.7)MgCl as a catalyst for reacting norbornadiene with 1,3-pentadiene.